Operating system apps

wanted to boot from the stick apparently, so emulating launchers (virtual machines, quemu etc) will not help much, since they are more for experimenting and fun rather then real daily work when run from stick.

Creating bootable stick is offered by almost any current linux distro, so this can be an alternative, provided the PC is capable of booting from the stick. But even this is rather theoretical use due to the speed of the flash.
And as the computer in questione here seems to have problems with running XP, it might be older then abt 4 years, thus the chance being able to boot from a stick is rather small.
And running for example a current version of ubuntu linux on a machine running into problems on XP is even more questionable. The current Linux distros dont use less resources then current windows. Yes 10 years ago linux was definitely choice for older and less powerfull hardware, but the current distros will run on current hardware only. My 6 years old laptop will definitely not run any current ubuntu for example.

Multiboot is alternative, since the OS are really separated here. One can use also the bootmanager of XP, not even big need for one of the commercial once, but yes the commercial once are much more simple to set up.

One of my computers has 9 operating systems on it, multiboot, still reasonable if machine power is not very high.

Sure, one could boot from stick, have a bootmanager on the stick, its starter in the MBR of the stick and have multiple partitions there and so be able to boot to different OS that way. I have not tried this so far myself, but have doubt that this is of any particular use due to the speed of the flash memories. The setup could be rather colmplex, since most OS will then need data and swap space somewhere, more then one partition on the stick will not be visible any way in most cases.

My collegue here in office has similar set up , but is using virual machines for all that, basic OS being vista which he does not use very often. But his PC is very recent version with quadcore and maximum ram etc, then the multiboot with all its work to set it up seems really to be the better alternative.

Well yes, one can use virtual box portable (google for it) and install into what ever needed. But one has to know the limitations of such virtual machine and also here consider the speed of the stick the use will be of no practical value probably.
One can try with moka5, they have lot of virtual machines ready for their setup, but also this will not run on any older computers.